Recording pressure-gage.



B. B. BRISTOL.

RECORDING PRESSURE GAGE.

APPLxcATxoN FILED APR. 1|. 190e.

191mm@ Patented Nw. 23, 1915.

2 SHEETS-SHEET l.

B. B. BRISTOL.

RECORDING PRESSURE GAGE.

APPLICATION FILED APII. II. I9oe.

Patented Nov. 23, 19V

WITNEEEEEI RM 1+ KM.

ATI-TVE,

BENNET B. BRISTOL, 0F NAUGATU'CK, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE FOXBORO COMPANY, 0F FOXBORO, MASSACHUSETTS, A. CORPORA- mron or MASSACHUSETTS.

RECORDTNG PRESSURE-GAGE.

Specicaton of Letters Patent.

Patented Nov. 23, i945..

l Application filed April 11, 1906. Serial No. 311,067.

To all whom t may concern.'

Be it known that l, BENNET B. aIS'JJoL, a citizen of the United States, resldmg at Naugatuck, in the county of New Haven, State of Connecticut, have invented an Improvement in Recording Pressure-Gages, of`

sure, the tendency to change of length beingj restrained by one or more flexible strips secured either within or without the tube to the inner or outer peripheral edges of the said diaphragm, said restraining strip or strips acting to prevent the elongation of that side of the tube to which it is secured while permitting free elongation of its opposite side, thereby to produce a resulting deflection of the free end of the tube which is utilized to indicate the amount of pressure. Ininstruments of this type, as at pres' ent constructed, reference being made to said patent for a more detailed description than is given here, each .restraining strip is composed of a flat band of metal secured to the tube by solder, necessarily applied on its 1nner or tube side. The presence of the solder has been found to impair the efficient action or resiliency of the strip and tube, so that while easily deflected, a return to normal position is not readily obtained, because of a permanent deflection or set produced by said solder. One feature of my invention resides in the provision of means to overcome this objection, whereby a sensitive instrument is secured that will indicate and record all variations of pressure Without appreciable error. This and other features of my invention, however, will be best understood and appreciated from the following description, when taken in connection with the accompanying drawings of an instrument embodying one form of my invention, its scope being more particularly pointed out in the appended claims.

Referring to the drawings,-Figure l 1s a front elevation of a complete instrument selected for purposes'oi:l illustration; Fig. 2, an enlarged sectional detail of the lower end of the expansion tube to show the manner of securing the flexible strip thereto; Fig. 3, an enlarged elevation of the right side of the expansion tube to show the flexible strip and the adjustable connection of the inking pointer thereto; Fig. 4, an enlarged detail of a portion of the flexible strip; Fig. 5, an enlarged plan and partial section of the top of the tube on line 5-5 (Fig. 3), with parts broken away; Fig. 6, a detail view of the lower sections of the inking pointer; Fig. 7, a modified form of the flexible strip; Fig. 8, a vertical section of a modified form of tube; Fig. 9, a similar view to Fig. l, showing my invention applied to a differential pressure recorder; Flg. 10,V a detail of the restraining strip and the form of pointer used therewith; and Fig. 11, a sectional detail of a usual type of expansible section of which pressure tube is composed.

In the embodiment of my invention illustrated, the instrument is provided with a suitable case, l, within which is mounted the pressure recording mechanism comprising a chart 2, rotated by the usual clockwork (not shown), the pressure expansion tube 3, and its inking pointer or pen arm 4.

The bottom of the tube 3 is provided with a head 5, (Fig. 2) secured and supported in a vertical position within said case, said head having an opening therethrough and a nipple 6 communicating therewith and receiving the pipe 7, (Fig. l) which is connected to 'any fluid containing receptacle, the pressure of which is to be indicated or recorded.

The expansion tube comprises, in the present instance, (see Fig. a plurality of independent sections 8, each formed of two fiat rings or diaphragms 9, having concentric corrugations.. These diaphragms are suitably united at their edges to form a series of expansion chambers 10, communicating and forming a continuous tube by openings l1, in their centers. A tube of desired length ton 12, the lower diaphragm being secured to said head 5, with its opening 11, communicating withsaid nipple 6 and the pipe 7.

As thus constructed, the tube as a whole tends to elongate or contract when subjected j to variations between the internal and external pressure, an increase or decrease in the internal `pressure while theexternal pressure remains constant respectively causing an expansion or contraction of the sections `0f the tube and ay consequenttendency to elongate or contract the tube. vSimilarly under constant internal pressure, increase or decrease of external pressure tends to produce respective contraction or elongation of` the tube. This tendency to elongate or contract, however, is prevented at one side of the tube by suitable restraining means, so that the tube is deected to one or' the other side proportionate to the variations between said pressures. For restraining the tube to roduce such defiections.; any suitable numer of restraining stripsvmay be Iemployed which are suitably connected to and at one side of the tube, butone, however, being provided in the present embodiment of my invention. As herein shown a flexible strip 13, preferably of the same metal as 'that of which the tube is composed or of a metal having approximately the same coefficient of expansion under varying temperatures, is secured along one edge of the tube and an important feature of my invention resides in the improved 'form and manner in which said flexible strip 13, is secured to the expansion tube, so that while said strip restrains the elongation of one side of the tube as its internal pressure increases, thereby causing a deflection of said tube'and strip, there shall so far as possible be no solder or other material on the flexing surfaces of said strip to impair the resiliency of the strip and therebypprevent its return to the verti-.

cal or normal position under normal pressure, thereby overcoming the objectionable setting or permanent defection caused by the use of n solder for securing the diaphragm sections to the body of the ystrip and which has interfered with the resilient action thereof. In the embodiment illustrated said means comprises a series of 'out-turned lips or ears 14 (Figs. 2 and 5) died out or' struck up from the strip itself and preferably along its medial longitudinal portion and bent at an angle thereto, the number'of lips and the space or interval between them respectively corresponding to the number of diaphragm sections in the tube and the interval between them, so .that said lips and sections may readily be connected together by any suitable means, as solder, said lips in the present instance constituting the attaching elements or mem- ,bers by means` of which the strip is secured to and along one side of the tube. In securing said strip 13 to the tube'it is placed along one edge thereof, with each of vsaid ears 14, resting against the peripheral or circumferential edge of an adjacent section'or diaphragm to which it 1s secured by suitable -means Preferably when in such position,

cent the edges of each of the slots 15, which are formed by inturning saldears 14 'in opposite directions, said lips receiving between 'them the edge of a diaphragm in which position it is secured by soldering, as has been described. By thus arranging a plurality o f continuous strip portions at the opposite side of eachl series of attaching ears, a more l perfect balance and action is obtained than would be the case if a single strip only were used at one s ide of such series of attaching ears, but my invention of course is not limited in this respect.

By forming the strip with lips or ears 14 or 14, and slots -15 or 15, greater durability and resiliency are secured than 1s possible with a lighter solid strip and by the use of attaching ears no foreign metal need 'be applied to the resi-lient and flexing portion on either side of or along the flexing surfaces or sides of the strip to impair or interfere with its resiliency or affect its elasticity, so that its responsiveness is not limited, and when deflected it will always return to normal position under normal pressure, said structural means preventing any tendency to a set in said strip and tube.

In instruments of this kind, any variations between the external pressure and that within the tube or other responsive member causes a contraction or expansion of the several sections and consequently of said tube in the direction of its length. This tendency being restrained at one side of the tube by the strip the unrestrained tendency at the opposite side of the tube causes the upper or free end of the tube to be deflected toward or from the restrained side of the tube for utilizing this movement to measure 'the pressure to which said. deflection is due, an ink- 1ng pointer or pen arm 4 is provided, adapted not only to.indicate but to record the amount thereof.

Hitherto the inking pointer or pen arm has been secured or attached to the free end -of the tube and usually to the upper dia- 1,1c1,37c ma relative to said stri and also to the chart 2,

and permit said arm 17, to be slid longitudinally thereon to adjust it in any desired position. The other arm 19, of this angular section 16, is in this instance arranged across the front of the tube and is'provided with a headed stud or pin 2O at its outer end, which is slidably secured in a longitudinal slot 21 in the end of the intermediate pointer section 22, the head of said stud engaging the sides of said slot and permitting said intermediate section 22 to be longitudinally or angular-ly adjusted relative to said arm section 16 or the strip 13. The stud and slot are arranged to form a friction joint so that the sections 16 and 22 are firmly held and may be secured in adjusted position.

The upper end of the intermediate section is pivotally connected tothe pen section 23 of the pointer, which enables it to be swung into any desired position laterally. 0f these three adjustable connections, onepermits longitudinal motion only to increase or diminish the length of the pointer, and one angular adjustment; the intermediate one permitting both adjustments, and all together enabling the inking portion 24 of the pointer to be placed in any desired position upon the chart or dial 2.

As hitherto constructed each of the eX- pansible sections of the pressure tube have tapered from their centers to the periphery so that the inner surfaces of the disks d against which the pressure of the contained A fluid acts, have been inclined to the diametral plane of said section, as illustrated in Fig. 11. In operation these disks are separated by pressure and assume the position shown in dotted lines d', requiring more pressure for further separation than when in normal position, and producing unequal deiiections of the tube for equal differences of pressure obviously resulting in the use of a variable scale instead of a uniform one. To remedy this defect, the expansible section diaphragms 9 (Figs. 1, 2 and 3) are arranged parallel to the medial diametral plane of the section or are dished as illustrated in Fig. 8, the diaphragms 9a being closer together adjacent their communicating opening or channel 11a than at their outer portions. Referring to Figs. 2 and 8, it will be noted that the outer peripheral portions of the diaphragms are bent inward vertically and then horizontally, the horizontal edge portion of eachforming a convenient surface to engage 'that of the opposed diaphragm, said surfaces being suitably secured together by any suitable means as by solder. rlhe vertically turned or bent portions together form a wall by which the diaphragm surfaces are separated or held apart, each of the diaphragms preferably forming an angle therewith of not more than 90, the separation of the diaphragms adjacent to said wall being equal to the maximum separation between them. This arrangement presents the inner surfaces of the diaphragms at a more desirable angle and to effect a more uniform separation thereof for equal variations of pressure and consequently a more uniform movement thereof and of the connected indicating or recordmg arm 1. By constructing the sections 1n this manner the pointer swings over the entire range of the scale or chart 2, uniformly in either direction and permits the u se of a uniform scale or chart, the deflectlons of the tube and consequently of the pointer carried thereby corresponding to the same variation of pressure throughout the range of pressure to which the tube is subjected.

In the embodiment of my invention illustrated in Fig. 9, two pressure tubes or other responsive members are employed each of which communicates by its nipple 6 and pipe 7a with a different pressure receptacle, the tubes being secured to the oppositely bent'attaching ears 14, 14b of a restraining strip 13 in the same manner as in the form shown by Figs. 1-3.

The attaching end of the pointer or pen arm however is obviously of a different construction (see Fig. 10) the arm 17a having a reversely bent end constituting a spring it being placed astride one of the attaching ears 14h.

rlhe pointer or pen arm is preferably bent back upon itself to provide a loop or elbow 27, to embrace the chart 2 and dial 28 and permit the top of the tube to be placed behind the bottom of said chart 2 and dial 28, thus enabling a shorter casing 1a to be used than in the type illustrated in Fig. 1.

By using the form of diaphragm sections illustrated in Figs. 2 and 8 far more ei cient results are securedv than is possible by the use of the type illustrated in Fig. 11, and which are commonly employed, for if each tube is subjected to pressures, approximately. for example, 100 lbs., and one eX- ceeds the other by a 5 lbs. and defiects the tubes and pointer or ink arm over the chart it is evident that this movement does not correspond and is not equal to that made when the pressures approximate 25 lbs. and differ by the same amount. This is evident since a greater pressure is required to pro; duce a given delection when the diaphragms are in the position indicated by reference The differential gage Fig. 9 is also provided with what may be denominated truss frames 29, 30, rigidly and respectively connecting the top and bottom sections of the two tubes with the upper and lower ends of the restraining strip 13, thehead 5 supporting the tubes only at their bases and thus permitting their upper ends or heads to be deflected together to one or the other side and proportionate to the excess or variation of pressure. By comparing this gage with that shown in Fig. 1- it is apparent that in the latter the sections 8 are only restrained at the point'swhere they are connected with the restraining strip l3,.and as the pressure within the tube is increased the opposite or left edgev of the sections will separate more than their innerl edges and before any deflection is edected. This construction therefore causes the instrument to be less sensitive A and accurate than` it ought to be'and it is to overcome this defect that the trusses are used; their action` being to prevent longi? tudinal separation ofthe sections except as permitted by the resulting deflection of the strip.

The differential gage (Fig. 9) operates as sure in one tube varies from that of the other and as the tubes are united at their heads by the truss frame 29, the relatively greater expansion of one tube due to its excess of pressure acts directly upon said frame and by the restraint imposed by the strip 13 produces a deflection of the two tubes together and proportional to such excess.. This arrangement produces a very sensitive, compact, andl reliable instrument with a uniform scale and which is entirely free from irregularity in action or tendency to set.

The chart 2, makes one revolution, say, every twenty four hours, and is graduated with radial arcs and concentric circles, the

divisions thereof respectively corresponding to pressures and hours of the day. The pen 24 carries suitable inking material and traces a line upon the chart corresponding to the varying pressure within ,the tube 6, pipe 7, andvessel. to which the latter is connected, said line being continuous and constituting a complete record of the pressure and its fluctuations for the twenty-four hours or day. The chart, however, may b e also equally adapted to record change in external pressure by maintaining the internal pressure constant whatever be its amount. A lt will be understood that my invention is not limited to the specific embodiment herein selected for illustration purposes only, nor to its details and arrangement of parts but that the same may be modified within wide limits without departing from the spirit and scope thereof.

Claims:

1. A pressure indicator comprising an expansion tube having a series of diaphragm sections, a. restraining strip therefor provided with a plurality of attaching members extending laterallyfrom the body of saidstrip for 'connection with a plurality of said sections.

2. ,A pressure indicator comprlslng an expansion tube provided with a series of diaphragm sections and a restraining strip therefor having its sides devoid of foreign matter such as solder, said strip being provided vvith a plurality of laterally extending members connected adjacent their outer ends witha plurality of said sections.

3. A pressure indicator having an eXpansion tube composed of a plurality of eX- pansible sections and a restraining strip arranged along one side of said tube and provided with a series of lips or ears, extending laterally from said strip, a plurality' ot which are connected with a plurality of said sections, to prevent elongation of said slde .upon a change of the external or internal pressure to which said tube is normally subjected and acting to produce a deiection of said tube, and an indicating or recording arm movable therewith and dclected by movements thereof.

4. A. pressure indicator comprising an expansion tube having a series of expansible sections and a restraining strip having a plurality of attaching elements bent transversely for connections with a plurality of said sections.

5. pressure indicator comprising an expansion tube having a series of expansible sections, a restraining strip having one 'or more straight sides, and an adjoining pormenare 7. A pressure indicator comprising an eX-' pansion tube provided with a pointer, a restraining stripv having a series of ears arranged longitudinally along a medial portion thereof and extending transversely therefrom, a plurality of said ears being se cured to one side of said tube and acting to cause a deflection thereof and of said pointer upon a change of external or inter-- knal pressure, one of which 1s normally constant.

8. A pressure indicator comprising an expansion tube and a restraining strip, longitudinally arranged on one side thereof, having a series of lateral projections, a plurality thereof being secured to said tube, and an adjustable pointer provided With means for adj ustably connecting it With said strip.

9. A pressure indicator comprising an eX- pansion tube and a restraining strip, longitudinally arranged on one side thereof, having a series of lateral projections, a plurality thereof being secured to said tube, and

a pointer having means for varying its length, adjusting` it laterally, and for adj ustably connecting it With said strip.

10. In a pressure indicator, an expansion tube, a restraining strip therefor, and a pointer having a slidable connection With said strip to permit its adjustment thereon and relative thereto.

11. In a pressure indicator, 'an expansion tube, a restraining strip therefor, and a pointer having means for embracing said strip to permit adjustment relative thereto.

12. ln a pressure indicator, an expansion tube, a restraining strip therefor, and la pointer having means comprising clips for slidably securing it on said strip to permit said pointer being adjusted longitudinally thereon. A

13. A pressure indicator comprising an expansion tube provided vvith a series of diaphragm sections, a restraining strip therefor having aA plurality of attaching elements transversely arranged relative thereto for connection vvith a plurality of said sections, a marking pointer connected with the free end of said tube, in combination With a chart, .over'vvhich said marking pointer is arranged to move to record the pressure.

14. A pressure indicator comprising an expansion tube having a series of expansble sections, a restraining strip having attaching elements arranged transversely relative to the length of said strip and forming exterior to the linear surfaces of said strip connections With a plurality of said sections, a marking pointer connected with the free 'end of said tube, in combination with a chart, over which said marking pointer is arranged to move to record the pressure.

15. ln a differential pressure indicator, a plurality of pressure tubes each comprising eXpansible sections, a restraining strip provided with ears extending in opposite directions relative to said strip and connected vvith the edges of the sections of said tubes and acting to produce a deflection of said tubes as they are subjected to unequal pressures.

16. ln a pressure indicator, the pressure tube 3 comprising expansible sections 8 and a restraining strip 13 provided with integral lips for connection with a plurality of said sections.

17. In a device of the type described, a pressure tube provided' With a series of eX- pansible diaphragm sections, a restraining device arranged at one side of said tube and connected With a plurality of said diaphragm sections, and auxiliary truss connections uniting the end portions of said device With the adjacent ends of the tube, normally preventing separation of the peripheral portions 0f said sections at the side of said tube opposite to that uponv which said device is connected` and coperating therewith to produce simultaneous deflection of said tube and said device. v

18. ln a pressure indicator the pressure tube 3 comprising expansible sections 8, and a restraining strip 13 provided with integral lips for connection With a plurality of said sections, and a pointer A connected vvith and movable with said tube.

19. A differential pressure gage comprising a pair of pressure tubes each composed of a plurality of expansible diaphragm sections and a restraining strip intermediate the tubes and connected therewith.

20. In an instrument of the character described, the combination of a pointer device; responsive means to govern the pointer device; a support for the pointer device intermediate the responsive means and the pointer device; and means for holding the pointer device fixed With relation to the support during the operation of the instrument vvhile permitting relative adjustment of the tvvo both lengthwise and transversely of the pointer device, said means including a slotted connecting element betvveen the pointer device and its support.

'21. In an instrument of the class described, the combination of a plurality of responsive members placed side by side each composed of a plurality of expansible diafili phragm sections whose axes are spaced apart and substantially parallelly arranged; a Hexible restraining member common to and attached to the marginal portions of said sections of the responsive members; and a device governed by conjoint response of said members.

22.: In an instrument of the class described, the combination of rigidly connected separate Opposed responsive members having separate sources of control and having conjoint responsive movement in a curvilinear path; and a device governed by conjoint -operation* Of said responsive members.

23. In an instrument of the class described,

a plurality of separate responsive members having homologous ends stationary and their Opposite ends rigidly connectel; and having capacity for conjoint responsive movement' in a direction transverse to their common median line, and a governed device gperated by conjoint response Of said memers In testimony whereof, I have signed my name to this specification, in the presence of two subscribing Witnesses BENNET B. BRISTOL.

Witnesses:

W. E. GOODYEAR, E. H. BRISTOL. 

